/*
 * Copyright 2004-2005 The Apache Software Foundation or its licensors,
 *                     as applicable.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.jackrabbit.core;

import java.io.Serializable;

/**
 * <code>ItemId</code> serves as the base class for the concrete classes
 * <code>PropertyId</code> and <code>NodeId</code> who uniquely identify
 * nodes and properties in a workspace.
 */
public abstract class ItemId implements Serializable {

    /** Serialization UID of this class. */
    static final long serialVersionUID = -9147603369595196078L;

    /** Memorized hash code. */
    protected int hash;

    /**
     * Creates an empty item ID instance.
     */
    protected ItemId() {
        hash = 0;
    }

    /**
     * Returns <code>true</code> if this id denotes a <code>Node</code>.
     *
     * @return <code>true</code> if this id denotes a <code>Node</code>,
     *         <code>false</code> if it denotes a <code>Property</code>
     * @see PropertyId
     * @see NodeId
     */
    public abstract boolean denotesNode();
}

